The invention relates to a method for non-destructive inspection of defects in a surface of a pipeline or storage tank for hydrocarbon transport or storage.
In a known method of pipeline or tank inspection, for example based on Magnetic Flux Leakage (MFL), an in-line inspection tool is moved along for example the pipeline. Defect patterns determined by such a method in general provide information about defect dimensions and defect locations in a surface of the pipeline. Mitigation plans, such as repair and replacement of the pipeline, are based on the defect patterns. However, usually there is a systematic error related to the defect patterns, giving rise to insecurity about for example a failure pressure of the pipeline. Because failure of the pipeline must be prevented, interpretation of the inspection results for mitigation plans is rather conservative. This may drive up a number of digs in a pipeline rehabilitation project and often give rise to unnecessary costs.